PROJECT SUIVIMARY (See instructions): Advanced stage low-grade ovarian serous cancer (OSC) represents approximately 10% of all advanced stage ovarian serous carcinomas. While the 5-year survival rates of patients with the disease is significantly higher than those with high-grade OSC, most patients with low-grade OSC eventually succumb to their disease. Recent genetic and genomic studies have shown that low-grade OSC and high-grade OSC have different pathogenetic pathways. Furthermore, recent clinical evidence has indicated that low-grade OSC is a unique disease and is less sensitive to standard chemotherapy. In spite of differences in histology and clinical outcomes, patients with low-grade or high-grade OSC are currently treated with the treatments, which are not that effective in low-grade OSC. Thus, new therapeutic strategies and novel molecular targets are desperately needed to improve the outcome of this patient cohort. Recent studies have demonstrated that the MAP kinase pathway is activated predominately in low-grade OSC because of activating KRAS/BRAF mutations or other unknown mechanisms suggesting that molecules targeting the MAP kinase pathway are promising therapeutics. In collaboration with the Gynecologic Oncology Group, we recently initiated a phase II clinical trial (GOG 0239) targeting the activated MAP kinase pathway in recurrent low-grade OSC using the MEK inhibitor, AZD6244, as a single agent. Preliminary analysis showed promising results with a number of responders in an initial data analysis. In addition, using microarray analysis on microdissected tumor samples, we identified activation of the IGF1-AKT pathway predominately in low-grade OSC. Furthermore, we recently showed that FOXOSa is a common target of PI3K/AKT, MEK/ERK, IKK signaling, and its localization and expression may be a predictor for AZD6244 sensitivity in low-grade ovarian cancer cells. Based on the results from these studies, we hypothesize that multiple signaling pathways are activated in low-grade OSC, and molecular markers identified through comprehensive genomic and proteomic analyses of responders and non-responders to pathway-targeted inhibitors can be used to predict drug responses and stratify patients for future clinical trials of pathway-targeted regimens. To test these hypotheses, we propose (1) to identify genomic and proteomic predictors of anti-tumor efficacy of the MEK inhibitor AZD6244 using GOG 0239 specimens;(2) to investigate the functional role of FOXOSa in conferring resistance to inhibitors of PISK/AKT and MEK/ERK kinases in low-grade ovarian cancer cells;(3) to investigate the IGF1-P1SK pathway as a potential therapeutic target for low-grade OSC;and (4) to develop clinical trials involving novel combined targeted agent approaches. We believe that our studies will help us to develop individualized treatment regimens that will have lower toxicity and higher efficacy, for women with low-grade OSC.